Adhesives are typically blended with other non-adhesive polymers or with adhesives to alter the final pressure sensitive adhesive properties such as re-positionability, adhesion to various surfaces, and control of drug agent delivery rates. Typically these encompass compositions where acrylic and silicone pressure sensitive adhesives, or other organic and silicone adhesives are blended.
Blended adhesive compositions are known in the art.
U.S. Pat. No. 5,725,947 describes a film composite wherein a first adhesive is an acrylic latex and a heat-activated urethane latex, a second adhesive is applied over the first yielding a re-positionable composite that upon extended contact builds adhesion.
U.S. Pat. No. 5,338,490 describes ionically conductive hydrophilic adhesive as a continuous phase and a hydrophobic adhesive discontinuous phase for biomedical applications.
Published U.S. Patent Application No. 2005/0282977 describes silicone pressure sensitive adhesive and silicone gel blend for skin-attachable use.
WO 2004094549 describes compositions wherein two adhesives, one with acidic functionality then other basic functionality, are blended then crosslinked.
Several transdermal patent applications exist wherein the active agent is incorporated into compositions of polymeric and/or pressure sensitive adhesives. Illustrative of these are the following:
Published U.S. Patent Application No. 20060078603 describes blends of acrylic adhesives with acrylic or rubber-based adhesives to provide desired drug flux in transdermal systems.
Published U.S. Patent Application No. 20050019385 describes blending low and high silanol concentration silicone pressure sensitive adhesives.
Published U.S. Patent Application No. 20060078601 describes acrylic-based adhesives with a second polymer selected from silicone, rubber, polyurethane, polyisobutylene, polyvinyl ethers, styrene block copolymers, polyether block copolymers, ethylene/vinyl acetate, vinyl acetate adhesives, polyvinylypyrrolidones and bio-adhesives.
Despite the disclosures contained in the above-described art, a need still exists for new forms of blended adhesive compositions providing good peel adhesion to a wide variety of surfaces, including flexible and rigid substrates.